(199c) Cell Size Patterns Wound-Induced Intercellular Ca2+ Flashes in a Developing Epithelium

Narciso, C., University of Notre Dame
Zartman, J. J., University of Notre Dame
Fletcher, A., University of Oxford
Garston, G., University of Oxford
Wu, Q., University of Notre Dame
Baker, R., University of Oxford

The propagation of Ca2+ through neighboring cells has been observed in a variety of cell types, including epithelial, glial, cardiac and muscle cells, and is mediated by many different stimuli. For example, Ca2+ flashes have been shown to provide the immediate initial response after wounding. To develop a quantitative understanding of the propagation of wound-induced Ca2+ flashes, we compare live-imaging of Ca2+ flashes in a genetic model of a developing epithelial organ with an in silico model that extends known conserved, general features of intracellular Ca2+ regulation. We consider the spatiotemporal dynamics of intercellular Ca2+ flashes in the Drosophila wing disc pouch, the primordium of the fly wing. We start with a well-established two-pool model of intracellular Ca2+ dynamics, and extend it to the full wing disc tissue by incorporating the effects of Ca2+ transport between cells via gap junctions. The computational model is refined iteratively to capture the observed dynamics of laser-induced flashes, namely a spatiotemporal asymmetric wedge that points toward the center of the disc.  By segmenting wing disc images we are able to simulate our model on a biologically realistic geometry, and hence understand how boundary shape influences flash propagation. Further, we demonstrate that variability in cell sizes across the disc plays a key role in explaining the spatiotemporal characteristics of Ca2+ flashes.